class back_account:
    def __init__(self,account_number,balance):
        self.__account_number = account_number
        self.__balance = balance  
    def deposit(self,money):
        if money <= 0:
            return f"金额异常：{money}"
        self.__balance += money
    def withdraw(self,money):
        if money <= 0:
            print("金额异常：",money)
            return 
        if self.__balance < money:
            print("金额不足")
            return 
        self.__balance -= money
        self.__pay_charge()
    def __pay_charge(self):
        self.__balance -= 10
    def __str__(self):
        return f"账户号：{self.__account_number},{self.__balance}"
        
        
cys = back_account("123456",1000)
# cys.withdraw(-300)
# cys.deposit(200)
print(cys.deposit(-300))
# cys.withdraw(-500)
# cys.withdraw(1600)
# print(cys.__account_number)
# print(cys.__balance)

print(cys)

        